The invention relates to a device for brewing beverages, in particular hot beverages, such as coffee and tea, which device comprises a filter unit, a brewing housing which interacts with the filter unit, can move up and down with respect to the filter unit and has an at least partially open base, a collection chamber which is in communication with the filter unit and has a closable outlet for discharging the prepared beverage, feed means for feeding starting materials for the beverage which is to be prepared and water to the brewing housing, and a control device for controlling the various components and functions of the device in a coordinated manner.
A device of this type, in particular in the form of a vending machine, is known in the art. The known device comprises a brewing housing (also known as an extraction chamber) with an at least partially open base, which is arranged above a collection chamber. A filter unit, in particular comprising a displaceable filter in strip form, is positioned between the brewing housing and the collection chamber. The collection chamber comprises a hollow cylinder with an outlet in its wall. A plunger is arranged moveably in the collection chamber.
To brew coffee, a metered quantity of ground coffee is deposited on the filter in the brewing housing, and hot water is then supplied. The plunger is moved upwards out of a bottom limit position in the collection chamber, so that air which is situated in the collection chamber is blown through the filter into the mixture of coffee and hot water, which has a beneficial effect on the extraction process and therefore on the quality of the coffee. After the desired extraction time has elapsed, the direction of movement of the plunger is reversed, so that the coffee is sucked out of the brewing housing through the filter into the collection chamber, and after the outlet has been opened, for example as a result of the plunger being displaced to below the outlet opening in the cylinder wall of the collection chamber, the coffee can flow out into a designated container, such as a cup or thermos flask. The brewing housing is then lifted off the filter, and the used part of the filter, together with the remaining coffee grounds, is discharged to a suitable waste receptacle. To prevent coffee residues from adhering to the wall of the brewing housing and thus having an adverse effect on the quality of the next beverage which is prepared, and also to prevent coffee residues from working their way through the machine, which could affect its correct operation and require cleaning work, the brewing housing is ejected from the filter unit using a sudden, powerful upward movement (also known as an xe2x80x9cupward clickxe2x80x9d), in order to clear the coffee grounds off the wall of the brewing housing so that they drop onto the filter before the filter is conveyed onwards.
However, it has been found that the residue, such as coffee grounds or tea leaves, though it detaches from the wall of the brewing housing as a result of the sudden upward movement, does not completely deposit onto the filter, and consequently the full desired effect is not obtained. The residue spreads undesirably through the device, such as between the top edge of the brewing housing and a feed funnel arranged above it for supplying raw materials, between the filter and the brewing housing, and even throughout the entire device. Such a spreading is undesirable from hygiene and fault aspects.
It is an object of the present invention to provide a device for brewing beverages in which the abovementioned drawbacks are eliminated altogether or occur to a greatly reduced extent.
The device of the type mentioned above, according to the invention, is for this purpose characterized in that the control device is designed in such a manner that the brewing housing can make a stroke downwards in order to clear the residue from the brewing housing.
Unlike in the known device, in the device according to the invention the brewing housing executes a downwardly directed, sudden movement (a so-called xe2x80x9cdownward clickxe2x80x9d), so that consequently the residue is also knocked off in the direction of the filter itself. This reduces the spread of the residue through the device, which is of benefit with regard to hygiene, maintenance and susceptibility to faults. This downward click is carried out after the extract has been sucked out of the brewing housing and before the filter is conveyed onwards or, in the case of a fixed filter, cleaned with the aid of a scraper or the like. Only the brewing housing moves when the downward click is being carried out with respect to the filter unit.